This one slipped by me. The App Store app on my Mac didn’t even register it. Anyway, lo and behold, 10.9.1 is out. Apple continues to add additional fixes to Mail for handling Gmail accounts. This one adds support for custom settings in Gmail. Here’s the complete change log;

Improved support for Gmail in OS X Mail, and fixes for users with custom Gmail settings

Improves the reliability of Smart Mailboxes and search in Mail

Fixes an issue that prevented contact groups from working properly in Mail

Resolves an issue that prevented VoiceOver from speaking sentences that contain emoji

Updates Shared Links periodically when open in the Safari Sidebar

Run to your local Apple download site, or open up the App Store app and hope it sees the update. Also, I recommend closing all apps and repairing file permissions both before and after applying the update. Happy Gmailing!